Gear pump



June 9, 1953 P, G, LINDBERG 2,641,192

GEAR PUMP Filed May 3, 1950 INV T PAUL G. L/ BE l MW ATTORNEY June 9,1953 P. G. LINDBERG 2,641,192

GEAR PUMP Filed May 5, 195o 3 sheets-sheet 3 j *Y J, a

'l mi \N i@ JNVENToR. PAUL G. L/NDaERG /M/"QML/ ATTORNEY Patented `lune9, 1953 GEAR PUMP Paul G. Lindberg, Willoughby, Ohio, assignor toLindberg Trust, Cleveland, Ohio, a trust of Ohio Application May 3,1950, Serial No. 159,673

(Cl. S- 126) 8 Claims.

This invention relates to pressure fluid gear pumps and has for one ofits primary objects to provide an improved gear pump of simplifiedconstruction and increased efficiency.

Another object is to provide a construction for automaticallymaintaining pressure responsive longitudinally iioating bearing bushingsin sealed contact with the side faces of the associated gears.

Another object is to provide an improved fluid pressure loaded iioatingend bushing construction which is also self-sealing with respect to thepump housing.

Another object is to provide an improved floating end bearingconstruction which is in the form of an elongated one-piece straightwall bushing to engage both adjacent journals of .the two gears and fillup the pump housing cavity so as to be a single self-sealing bushingthat necessitates no sealing accessories.

, Another object is to provide such a one-piece floating end bushingwith a pressure responsive sliding means for automatically maintainingproper pressure loading and alignment and sealing of the bushing withthe gear faces and the pump housing.

Another object is to provide such a one-piece floating end bushing andsingle pressure pin loading device therefor that will maintain properpressure loading, alignment and sealing and avoid cocking and whichbushing may support the gear journals as a plain bushing or have rollingbearing elements therein to support the gear journals.

With .the foregoing and other objects in view, the invention resides inthe combination oi parts and in the details of construction hereinafterset forth in the following specification and appended claims, certainembodiments thereof being illustrated in the accompanying drawings, inwhich:

Figure 1 is a view in elevation of the pressure inlet and outlet end ofthe uid pressure gear Dump;

Figure 2 is a top plan view of the pump;

Figure 3 is a View in section taken through the pump along line 3--3 ofFigure l;

Figure 4 is a view partly in top elevation and partly in transversesection of the pump;

Figure 5 is a View in section taken along line 5-5 of Figure 4;

Figure 6 is a View similar to Figure 3, showing the gear journalssupported by needle bearings in the bushings;

Figure 7 is a View in perspective of one of the gear journal bushings;and

Figure 8 is a view in section taken along line 8--8 of Figure 6.

Referring more particularly to the drawings, the main gear pump housingI has secured thereto by bolts 2 a housing 3 for the uid inlet 4 andoutlet 5.

The pump is shown to comprise two pump gears 6 and 'I with meshing teeth3 and 9. On opposite sides of teeth 8, gear 6 is provided with journalsIll and I I and on opposite sides of teeth 9, gear 'I is provided withjournals I2 and I3. Journal I I of gear 3 and journal I3 of gear 1 aremounted to rotate in an elongated unfianged one-piece straight sidebushing I4 which is mounted to be longitudinally slidable on the innersurface of housing member I5 and which fills up the housing cavity. Sucha bushing I4 is shown in perspective in Figure '7. Journal Ill of gear Eand journal I2 of gear 'I are mounted to rotate in a similar elongatedunflanged one-piece straight side bushing I6 that is likewise mounted tobe longitudinally slidable on the inner surface of the housing andlikewise fills up the housing cavity. The opposed faces II and I8 ofbushings I4 and I6 are pressure loaded to engage the opposite side facesof gear teeth 8 of gear Ii in uid sealing relationship, and the opposedfaces I9 and 20 of bushings I4 and I6 are pressure loaded to engage theopposite side faces of gear teeth 9 of gear I in uid sealingrelationship. Gears and I are provided with longitudinal bores 2I and22.

Journal I0 of gear 6 has a reduced extension 23 that is splined to acoupling member 24 having a flange 25 that engages with a bearing ring26, the opposite side of which presses against a flexible seal ring 2l,that, in turn, presses against a collar 28 provided `with an annularseal ring 2S between it and the housing and secured therein by a snapring 30. Coupling member 24 is secured by pin 3| to the splined gearconnector 32. A compression coil spring 33, bearing inwardly againstgear journal I0 is provided to eliminate end play of gear 6 andaffecting the seal assembly at this end of the gear.

Housings I and 3 when connected together are uid sealed by rings 34 and35. The fluid from inlet 4 passes through inlet chamber 36 to gear 'Iand from gear 6 the iiuid passes through outlet passage 31 to outlet 5.

Mounted in housing 3 is a spring and pressure loaded slidable pin 38provided with an annular seal ring 39. It is normally urged by acompression coil spring 40 in the recessed head of the plug to initiallyresiliently force the onepiece gear bushing I4 to the left, as viewed inFigure 4, which leaves an axial chamber 4I between the housing 3 andbushing i4.

Fluid pressure is fed in from the high pressure side from passage 3lthrough passage i8 in behind and in the recessed head of oating pin 38to force the pin 38 to the left to fluid pressure load the .bushing I4.Pressure loaded pin 36 is located approximately opposite the center ofinternal pressure and on the horizontal centerline, but displacedoutwardly from the vertical centerline, as shown in dotted lines inFigure 8. The resulting action of pressure fluid from the high pressure,or discharge, side on the pin 38 is to pressure load the bushings.Pressure iluid in space 50 behind 'bushing IB and behind spring 33 isvented through passage 5I and bore 2I to space 4I behind bushing I4.

Housing 3 is provided with a bore 42 to ,receive a retaining plug 43 anda coil spring 44, urging a ball valve 45 to normally close passage 46that communicates with passage 41 leading to axial chamber 4I. Thisprovides a low pressure relief valve for venting chamber 4I to lowpressure through passage 4S to the inlet passage 36.

The one-piece floating bushings lI4 and I6 not only completely iill thehousing cavities, 'but are also elongated and straight sided with noflanges. `The intimate contact of their outer surfaces throughout theirentire lengths with the inner surface of the housing provides for aneiective seal against fluid leakage. They are thus selfsealing andrequire no additional sealing accessories. Another advantage of thisone-piece iloating bushing construction lies in the fact that it isself-aligning with respect to the geai journais, the gear faces and thehousing, with virtually no tendency to cock in their pressure responsivesliding movements. This latter is especially true because the singlebushing I4 is pressure loaded by the single pressure loaded pin 38 ,f

which is located approximately opposite the center of internal pressure.

In my gear pump construction, I have considerably reduced the number ofessential operating parts. By reason `of employing single one-piecestraight sided iloating bushings, I am able to employ a slidablepressure pin, or piston, 38 for effectively pressure loading the bushingI4 by applying the fluid pressure from the high pressure side to the pin38. Moreover, in such a construction I und it unnecessary to employinsert plugs to insure against leakage. The fluid that acciunulates inspace 4I, upon movement of bushing I4, is readily vented past the Wpressure 'ball check valve to the low pressure side. Thus I find itunnecessary to provide any relief recesses between the side faces of thegears and the bushings.

All of this is in contrast to conventional gear pumps employing separatepressure loaded bushings for each journal of each gear in 'which case itis necessary to use rubber inserts as fluid seals. Such inserts areplaced in drilled holes on the low pressure side connecting the ilats ofboth the adjacent floating bushings and the pump housing to keep thehigh pressure in chambers behind the bushings from by-passing directlyto the pump inlet. Failure of such rubber inserts results in failure ofthe pump. Conventional pumps also employ reliefs on the faces of theflanges of the oating bushings as a means for controlling the magnitudeof the pressure loading. Conventional gear pump construction, moreover,precludes the use of rolling bearing elements, such as ball, roller orneedle bearings, inasmuch as the cocking tendency of the bushingsemployed for each `journal of each gear results in an overload on thebearing elements.

Due to the nature of my construction, however, I may employ plainbushings, as described, or I may also employ rolling bearing elementscarried by the bushings to support the gear journals. I have shown suchan arrangement in Figure 6, in which the general overall constructionremains the same as previously described, with the exception that I haveshown needle bearings 52 carried by bushing I4 to support journal II ofgear 6 and needle bearings 53, also carried 'by the same bushing I4 tosupport journal I3 of gear I. Likewise, I have shown needle bearings 54carried by bushing I6 to support journal I0 of gear 6 and needlebearings 55 carried by the same bushing I6 to support journal I2 of gear'I.

While I have described as a preferred embodiment of my invention the useof a single pressure responsive floating pin 38 for pressure load- .ingthe one-piece bushing I4, in some instances it may be desirable toemploy more than one of such pins when it is desired to more evenlydistribute the pressure loading force across the back face of thesliding bushing I4 when the latter is of larger sizes in larger gearpumps.

I claim:

1. A gear type pump comprising a hollow housing having a fluid inlet andoutlet, said housing having a gear chamber and an auxiliary chamber insaid housing between said gear chamber and said outlet, a pair ofmeshing gear members mounted in said gear chamber, each of said gearmembers having journals extending from the opposite faces thereof, anelongated one-piece bushing having flat front and back end faces, said'bushing having straight side walls connected 'by curved ends, saidbushing being mountedto have its entire periphery longitudinallyslidable in contact with the inner surface of said hollow 'housing, saidbushing being arranged axially of the adjacent axial faces of both ofsaid gear members, said bushing surrounding and supporting the adjacentparallel journals of both of said gears and having a front `axial facecooperable with the adjacent axial face of its associated gear membersto lprovide a seal between said bushing and said gear members and apiston slidably mounted in said auxiliary chamber in said hollow housingand in axial contact "with the back face of said bushing and a fluidpassage leading from the pump discharge outlet to said auxiliary chamberon the back face of said v piston vto lprovide a fluid pressure loadingon the back of said bushing to urge said bushing against saidgears.

2. A gear type pump comprising a hollow housing having a fluid inlet andoutlet, said housing having a gear chamber and an auxiliary charnber insaid housing between said gear chamber and said outlet, a pair ofmeshing gear members mounted in said gear chamber, each of said gearmembers having journals extending from the Upposite faces thereof, anelongated one-piece bushing having flat front and back end faces. saidbushing having straight side walls connected by curved ends, saidbushing being ,mounted to have its Ientire periphery longitudinallyslidable in contact with the inner surface of said hollow `housing, saidbushing being arranged axially o1' the adjacent axial faces of both ofsaid gear members, said bushing surrounding and supporting Athe adjacentparallel journals of both of said gears and having a front axial facecooperable 5, with the adjacent axial face of both of its associatedadjacent gear members to provide a seal between said bushing and saidgear members, a piston slidably mounted in said auxiliary chamber insaid hollow housing, said auxiliary chamber being axially removed fromsaid bushing, said piston being in axial contact with the back face ofsaid bushing and a fluid passage leading from the pump discharge outletto said auxiliary chamber on the back face of said piston to provide afluid pressure loading on the back face of said bushing to urge saidbushing against said gears.

3. A gear type pump comprising a hollow housing having a fluid inlet andoutlet, said housing having a gear chamber and an auxiliary chamber insaid housing between said gear chamber and said outlet, a pair ofmeshing gear members mounted in said gear chamber, each of said gearmembers having journals extending from the opposite faces thereofanelongated one-piece bushing having flat front and back end faces, saidbushing` having straight side walls connected by curved ends, saidbushing being mountedlto have its entire periphery longitudinallyslidable in contact with the inner surface of said hollow housing, saidbushing being arranged axially of the adjacent axial faces of both ofsaid gear members, said bushing surrounding and supporting the adjacentparallel journals of both of said gears and having a front axial facecooperable with the adjacent axial face of its associated adjacent gearmembers to provide a seal between said bushing and said gear members, apiston slidably mounted in said auxiliary chamber in said hollowhousing, said auxiliary chamber being axially removed from said bushingand of greater axial length than said piston, said piston being incontact with the back face of said bushing and a fluid passage leadingfrom the pump discharge outlet to said auxiliary chamber on the backface of said piston to provide a fluid pressure loading on the back faceof said bushing to urge said bushing against said gears.

4. A gear type pump comprising a hollow housing having a liquid inletand outlet, said housing having a gear chamber and an auxiliary chamberin said housing between said gear chamber and said outlet, a pair ofmeshing gear members mounted in said gear chamber, each of said gearmembers having journals extending from theopposite faces thereof, anelongated one-piece bushing having ,flat front and back end faces, saidbushing having straight side walls connectedzby curved ends, saidbushing being mounted to have its entire periphery longitudinallyslidable in contact with the inner surface of said hollow housing, saidbushing being arranged axially of the adjacent axial faces of both ofsaid gear members, said bushing surrounding and supporting the adjacentparallel journals of both of said gears and having a front axial facecooperable with the adjacent axial faces of both of said gear members toprovide a seal between said bushing and said gear members, a pistonslidably mounted in said auxiliary chamber in said hollow housing, saidauxiliary chamber being axially removed from said bushing and of greateraxial length than said piston, said piston being in contact with theback face of said bushing to urge said bushing against said gears, aliquid passage leading from the pump discharge outlet to said auxiliarychamber on the back face of said pin to provide a liquid pressureloading on the back face of said bushing and venting means for venting6, liquid from any space between said bushing and said gear journals andbetween said bushing and said housing to the low pressure inlet side ofsaid pump.

5. A gear type pump comprising a hollow housing having a liquid inletand outlet, said housing having a gear chamber and an auxiliary chamberin said housing between said gear chamber and said outlet, a pair ofmeshing gear members mounted in said gear chamber, each of said gearmembers having journals extending from the opposite faces thereof, anelongated one-piece bushing having flat front and back end faces, saidbushing having straight side walls connected by curved ends, saidbushing being mounted to have its entire periphery longitudinallyslidable in contact with the inner surface of said hollow housing, saidbushing being arranged axially of the adjacent axial faces of both ofsaid gear members, said bushing surrounding and supporting the adjacentparallel journals of both of saidgears and having a front axial facecooperable with the adjacent axial faces of both of said gear 'membersto lprovide a seal between said bushing and said gear members and apiston slidably mounted in said auxiliary chamber in said hollowhousing, said auxiliary chamber being axially removed from said bushingand of greater axial length than said piston, said piston being incontact' with the back face of said bushing to urge said bushing againstsaid gears, a liquid passage leading from the pump discharge outlet tosaid auxiliary chamber on the back face of said piston to provide aliquid pressure loading on the back face of said bushing and ventingmeans, including a low pressure relief valve therein, for venting liquidfrom any space between said bushing and said gear journals and betweensaid bushing and said housing to the low pressure inlet side of saidpump.

6. A gear type pump comprising a hollow housing having a fluid inlet andoutlet, said housing having a gear chamber and an auxiliary chamber insaid housing between said gear chamber and said outlet, a pair ofmeshing gear members mounted in said gear chamber, each of said gearmembers having journals extending from the opposite faces thereof, apair of unilanged elongated one-piece bushings, each having a flat frontand back end face, each bushing having straight side walls connected bycurved ends, each bushing being mounted to have its entire peripherylongitudinally slidable in contact with the inner surface of said hollowhousing, said bushings being arranged one on each side of said pair ofgear members and axially adjacent the two opposite axial faces of bothof said gear members, each of said bushings surrounding and supportingthe adjacent parallel journals of both of said gears and having a frontaxial face cooperable with the adjacent axial face of its associatedgear members to provide a seal between said bushings and said gearmem-bers and a piston slidably mounted in said auxiliary chamber in saidhollow housing and in axial contact with the back face of one of saidbushing members and a uid passage leading from the pump discharge outletto said piston to provide a fluid pressure loading on the back face ofsaid last named bushing.

'7. A gear type pump comprising a hollow housing having a fluid inletand outlet, said housing having a gear chamber and an auxiliary chamberin said housing between said gear chamber and said outlet, a pair ofmeshing gear members mounted in said gear chamber, each of said gearaan; raaf membersrhairingA j ournalsz. extending; from-,1th 'ie-opy4vnesite: facesf; therecfi; a; pair..- of; unanged. clon--gatedone-piecebushingsaeach havinafaffiatlfront. and back end face, eachof said bushings having straight; side walls.; connected by, curvedends, eaclifbushing being. mounted toi-have its entire'- perinherylongitudinallyY slidablerin Contact; with4 thef inner" surface of'saidhollow` housing, said.- bushings, beingiarrangedone on,;each sideiofsaid. paifrofigear. members.- and.1 axially adjacent the' twas opposite;axial; faces: of; both ot said gearA members;v each.Y of saidibushingssuiu'ounding and supporting` the: adj acent.- parallelv journals of.yboth of; said-gears and. having a; front. axial facecooperabie: wtlrthe;adjacent. axial' face of itsassor ciatedgeait'membelzfto. provide.'allsealbetweenI said; bushings; and said gear; members., a piston slid--ably mounted: inlsa'id auxiliary chambe1'.r'in.said.- hollowr housingand in contactar-ith thebackv face.

offenes-o1"-Y said :.bushingsrto urge.4 the sama against..

s1aaid:.gea-rs-,l said: auxiliary chamber; being?l axially`removedf-rombna ofi` said; bushings and of., greater axialr length. thansaid piston anda iiuid" pas sage lea-dingiifrom the pump;discharge-outlet-toi said; auxiliary; chamber;v on. the bacia` face of,said. piston to; providela ud. pressureloading on the bacliifacev of;said;` bushing;

8:. A: gear typenumpcomprising a hollowy housing; having; auid inlet.andA outlet, said housing; haring;` a. gear;y chamber and an` auxiliarycham.= benin said; housing: andgbetween, said gearcham-l ben'anrtsaid;outlet, al pairfofiV meshingv gearmem bers. mounted in: said; gearchamben. each of4 said; gearmembers having' journals.; extending.v from;thefopposite; facesthereof.; ane] ong-ated one-piece, bushing having,IAdat front.. and back: end;- faces; said" bushing'havingfstraightsidewalls connected* curved ends;l said bushing being' mounted to haveitsentne periphery-` longitudinally siidabl'ei in contact with the innersurfaceoi saidvv hollow:

. ing.l andal fluid passage-.leading-from thefpurrm discharge.n outletI`td said auxiliar-y, chamber 0n: the: back face. of said.`piston.tolpruvidaai fluidiv pressureloading onrthefback' face oi .saidbushingj in; a; direction:v substantially opposite the.. centen otinternal pumpf-pmssure. l

BAUL. G. MNDBRG,

References; cited: im the; fue. of;l this pamrt UNITED: sauras- PATENTS

